1. Technical Field
The present disclosure relates to a heat dissipation system and more particularly to a heat dissipation system which is energy-efficient.
2. Related Art
Generally, electronic devices include desktop computer, laptop, tablet computer, personal digital assistant (PDA) and server, there are various types of electronic components inside an electronic device, and each electronic component has a temperature range within which it can operate normally. If the temperature of the electronic component exceeds the operating temperature range, it may operate abnormally, for examples the electronic device may be down or may be damaged due to the electronic component overheated. Fire may even breakout because of the overly high temperature. Therefore, most of the electronic devices employ heat dissipation modules, such as liquid cooling devices, in order to reduce the temperature of the electronic component. Thereby, the electronic component can be operated within the normal operating temperature range, so as to prevent the electronic component from operating abnormally.
The liquid cooling device has a pipeline, a radiator and a pump. The pipeline has a heat absorbing section and a heat dissipation section. The heat absorbing section is in thermal contact with an electronic component of the electronic device, and the heat dissipation section is in thermal contact with the radiator. Furthermore, there is a coolant inside the pipeline. When the pump drives the coolant to flow to the heat absorbing section, because the temperatures of the electronic components are higher than that of the heat absorbing section of the pipeline, the quantity of heat released by the electronic components will be conducted to the heat absorbing section of the pipeline. At this point, because the temperature of the coolant is lower than that of the pipeline, heat will be conducted from the pipeline to the coolant. Then, the temperature of the coolant increases because of the heat absorbed. Next, the coolant with a high temperature is sent to the heat dissipation section by the pump. Because the temperature of the coolant is higher than that of the radiator, the heat is released and conducted to the radiator through the pipeline so that the temperature of the coolant is lowered. Then the coolant with a reduced temperature will be sent back to the pump to complete a cooling cycle.
The abovementioned coolant can be maintained in single-phase without changes during the cooling cycle, and only the sensible heat of the coolant contributes to the cooling of the electronic component. Or, the abovementioned coolant can transform between liquid-phase and vapor-phase. In this case, the latent heat of the coolant absorbed during phase transition (i.e. changed from liquid phase to vapor phase) is involved to cool down the electronic component. The difference between the two lies in that the latent heat is a lot higher than the sensible heat.
However, even though the coolant is able to absorb a large quantity of heat released by the electronic components through phase transition, the flow resistance between the gaseous coolant and the pipeline is a lot higher than that between the liquid coolant and the pipeline. Therefore, after the coolant is vaporized, larger power is consumed by the pump in order to drive the coolant to cycle inside the pipeline. Also, when there is too much gaseous coolant inside the pipeline causing excessive flow resistance between the coolant and the pipeline, a compressor of higher power consumption is required to drive the coolant to cycle inside the pipeline. Therefore, achieving balance between an efficiency of temperature reduction and power consumption of the heat dissipation system is a problem.